1. Field of the Invention
The present invention relates to acatalyst component for addition polymerization, a catalyst for addition polymerization made by using thereof, and a process for producing an addition polymer.
2. Description of Related Arts
Since olefin polymers such as polypropylene and polyethylene are excellent in mechanical properties, chemical resistance and the like and excellent in balance between those properties and economical efficiency, they have been widely used for various molding fields. These olefin polymers have been conventionally produced by polymerizing an olefin using a conventional type solid catalyst (multi-site catalyst) which combines a solid catalyst component obtained by using a metal compound of Group IV such as titanium trichloride or titanium tetrachloride, with a metal compound of Group XIII represented by an organoaluminum compound.
A process for producing an addition polymer, which polymerizes an addition-polymerizable monomer using a so-called single site catalyst prepared by combining a transition metal compound which is different from a solid catalyst component having been used from old (for example, a metallocene complex) with an aluminoxane or the like, is recently proposed. For example, JP-A-58-19309 reports a process using bis(cyclopentadienyl) zirconium dichloride and methyl aluminoxane. Further, it is reported that a specific boron compound and such transition metal compound are combined. For example, JP-A-1-50203 reports a process using bis(cyclopentadienyl)zirconium dimethyl and tri(n-butyl)ammonium tetrakis(pentafluorophenyl)borate. The olefin polymers obtained by using these single site catalysts have a narrower molecular weight distribution than that obtained by the conventional type solid catalyst (multi-site catalyst), and further, a comonomer is more homogeneously copolymerized in case of a copolymer. Accordingly, it is known that a more homogeneous copolymer than a case of using the conventional type solid catalyst is obtained.
The improvement of such catalyst component for addition polymerization has been intensively studied, and the kinds of metals used for main catalyst components are widely reported over the respective Groups of the Periodic Table. For example, in Angew. Chem. Int. Ed. 38 428 (1999), it reported that a metallocene complex of the Group III to the Group XIII and non-metallocene compound are effective as the main catalyst components. On the other hand, as a co-catalyst component as an activator for combining with the metallocene complex or non-metallocene compound, an aluminoxane belonging to a compound of the Group XIII, a boron compound and the like have been mainly developed.
Further, when an addition polymer such as an olefin polymer is produced using a single-site catalyst, the molecular weight of the addition polymer obtained is usually low, and the improvement thereof has been desired. JP-A-6-329713 reports a catalyst component of polymerizing an olefin composed of an aluminum compound having an electron withdrawing group or a group containing an electron withdrawing group. An olefin polymer having a certain degree of high molecular weight can be obtained by using the aluminum compound. However, since it cannot be always said that the high molecular weight is adequately high, a novel catalyst component as an activator, which realizes the further improvement of high molecular weight, has been desired.